In contrast, in nine tumours with a PDGFRA mutation and one tumour with a KIT mutation, the expression of PDGFRA was ≤1.32 a.u., while in the remaining GISTs with KIT/PDGFRA mutations, it was ≤0.84 a.u. One tumour with a PDGFRA mutation exhibited overexpression of both KIT and PDGFRA. Among receptor wild-type GISTs, the expression profile for one tumour was typical for tumours with PDGFRA mutations and was typical in two others for tumours with a KIT mutation. This evidence concerns the gene KIT and neoplasm.